What happened
On 24 September 2015, at approximately 02:39 local time, a Shaheen Air International Boeing 737-40 and registration AP-BJR was prepared for departure from Sharjah International Airport, bound for Bacha Khan International Airport in Pakistan. During the taxi phase, the aircraft transitioned from taxiway Alpha 20 onto taxiway Bravo. Instead of utilizing the assigned runway 30, the flight crew initiated the takeoff roll on the parallel taxiway Bravo.
As the aircraft moved, the air traffic controller lost visual contact with the plane while it was transitioning between taxiways, only regaining sight of it once it reached the intersection of taxiway Alpha 18 and Bravo. Because the aircraft's speed was unknown and the taxiway was unoccupied, the controller allowed the takeoff roll to proceed. The crew completed the takeoff from the taxiway and continued the flight to its destination without further incident. There were no injuries recorded during the event.
The investigation
An investigation by the UAE Air Accident Investigation Sector (AAIS) utilized digital flight data and air traffic communications to reconstruct the taxi route. The analysis confirmed that the aircraft had indeed turned onto taxiway Bravo and utilized it for departure. The investigation also reviewed communications between the flight crew and air traffic control, noting that the crew did not realize they were on a taxiway during the takeoff roll and remained unaware of the error until notified by the operator several days later.
Findings
Investigators concluded that the primary cause of the incident was that the flight crew failed to properly monitor the taxi route, signage, or lighting, leading to a misunderstanding of air traffic control instructions and a failure to recognize they were aligned on a taxiway.
Several contributing factors were identified, including:
- The air traffic controller's loss of visual contact with the aircraft during taxi.
- The controller's decision to allow the takeoff to continue due to the lack of known speed and the sterile status of the taxiway.
- The presence of bright green lead-on lights for taxiway Bravo and similar numeric designations between the taxiway and runway.
- The fact that the red stop bar lights at the runway 30 holding point were turned off.
- The width of taxiway Bravo, which may have led the crew to assume it was the runway.
- The operator's standard operating procedures did not explicitly require the crew to verify they were lined up on the correct runway.
Safety action
Following the investigation, several safety recommendations were issued. These include requests for Sharjah Air Traffic Services to re-emphasize standard phraseology, read-back accuracy, and the responsibility of controllers to maintain visual contact. Additionally, recommendations were made to the Sharjah Department of Civil Aviation to review the risks associated with similar taxiway and runway designations, evaluate the need for "hot spot" designations at certain intersections, and consider the implementation of surface movement radar to improve monitoring.